How Can A Guzzi Fix Itself?

[SmithSwede]

Well, it seems like my Guzzi fixed itself.  Or just wanted to take a 5 month vacation.  How is this possible? 

Back in June, I had some kind of crank/no-start problem, and was pretty sure it was related to the crank position sensor circuit because I was getting zero spark and zero injected fuel.  I had a devil of a time, and I never could get it to start after swapping out multiple new sensors, cleaning electrical connectors, battery terminals and grounds, swapping relays, inspecting wiring, charging the battery, etc.   So I finally gave up and parked the thing until I had more time to fool with it or tow it to a professional.  Details:  https://wildguzzi.com/forum/index.php?topic=101903.0;wap2

I went to check the battery last week and just for giggles hit the start button.  Of course, it started instantly.   I've been riding it ever since, multiple trips, coming up on 400 miles, with zero issues.  Some trips are long (> 50 miles).  And each day I have experimented by starting it and shutting it off dozens of times, just to see if I can catch it not starting for some reason.  Nope, starts perfectly every time. 

What the heck? 

At first I though it was somehow temperature related.  It failed when it was super hot in July Texas weather, and it started for the first time in November during a cold front with temperatures in the 30s.  But it has been running fine now in the mid-70s.

I don't think it relates to the air gap between the head of the CPS sensor and the ring gear. If I loosen both mounting screws 1/2 turn and move the sensor away from the ring, it starts and runs fine.  It only fails if I back both mounting screws out one full turn.   So I'm pretty sure I'm not on the ragged edge of sensing due to incorrect air gap.

The only thing I can figure that makes any sense is that I sprayed Craig De-Oxit contact cleaner into every connector, relay, socket or other circuit that could conceivably have something to do with the CPS.  Maybe it took a while for the cleaner to bust some kind of corrosion and restore function to this 5 volt sensing circuit?

Thoughts?   

I'm glad it's working and don't mean to gripe, but I don't really trust it without knowing why it failed before and why it is now working ok.   Especially because when it failed back in July, it was the same deal---it had been running perfectly right up until the moment it stopped working at all, stranding me at the airport.

I'm not sure how I diagnose a potential wonky condition if the thing is working just fine now.

[Huzo]

They’re almost the worst ones...
The problem that manifests then hides. I can’t remember what you ride SS, how much electronic “wizardry” does it possess ?
Moisture in ECU giving a false command ?
Stored code/s ?
Something like that would shit me to tears, in some ways you’re better off if something breaks. I’m not good enough to help diagnose past where you’ve been, but good luck .

[80CX100]

Is it possible, that at some point the battery was disconnected, and the ecu reset itself and rebooted?

Maybe the cooler temp and deoxit overcame some resistance along the line, possibly one of the plugged in relays, solenoid etc?

I'm not up on all the digital stuff, but could you hook guzzidiag up to it and read the error clues?

I agree, very unsettling when it fixes itself but you don't know why.

Good luck

Kelly

[Groover]

I've experienced something similar with some computer motherboards, in my case it was a bad batch of can capacitors that were used on a certain generation computer (circa 2007), and somehow and magically would heal themselves sometimes. I didn't trust them after that of course, but had a few then work for a long time without issues after the initial fail signs (computer freezing typically). Not sure if those things have can capacitors in the ECU, guessing yes, so maybe that could be a possible culprit. Don't know, and really don't know what's inside those CPUs and how to check their health. Good luck

[davedel44]

Early Christmas Present?

Dave
Galveston

[SmithSwede]

Sorry Huzo.   To be clear, this is a 2013 V7 Stone small block with single throttle body.    I don’t have Guzzi Diag.

[Huzo]

Sorry Huzo.   To be clear, this is a 2013 V7 Stone small block with single throttle body.    I don’t have Guzzi Diag.

Ok mate..
I’m out.

[bigbikerrick]

Im happy its running now, SmithSwede. If it were mine,Just for peace of mind, I would get the Guzzidiag cables,and hook it up,and see what the readings are.I just picked up a set for my Griso,and they were only around $30.
Also , in case it acts up again, having the ability to run Guzzidiag I imagine would be a helpful in diagnosing the cause.
Rick.

[pat80flh]

Worst thing in the world to diagnose, an intermittent electrical problem.  To my mind, there are three possible problems:
    One ,  a bad crank sensor, I know you have a new one in there, and seem to remember you've put multiple new ones in, si this is doubtful.
    Two,  a bad ECU,  which I find unlikely, usually when they're bad, no run, and not intermittent.
    Three, wiring between ECU and CPS, most likely in my mind to cause intermittent pproblems.

   I think you're on the right track, and I would go back to every connection that the CPS signal passes through, especially check for hogged out female terminals. Sometimes the force and wiggling required to unseat an electrical connector can cause the terminal to become slightly misshapen.  A spare male terminal can be used for a "pin drag test". Sometimes a pin can be used to reshape or tighten up the connection. Sometimes just unplugging a connector can clean off an oxidized terminal.  The cold good/hot no good kind of says that when expanded(hot) the connection is poor. 

[Kiwi_Roy]

I think you have made an excellent attempt at diagnosing the problem, it could well be a bad connection
Please remind us again what model the bike is, for some reason I had this one in mind http://www.thisoldtractor.com/guzzi007/schematics/2013_V7_Series.gif
Perhaps see if you can pick up a new cable from the ECU to the sensor (37) in case there is something wrong with the one on the bike, it's a special cable designed to shield the signal, the wires are twisted and it has an overall shield. The signal from the sensor is very weak, there's really no Voltage to it at all just a small AC ripple.

My V7 has a little light monitoring the status of the relay (28), if I look under the seat I see it light up as the fuel pump primes then again as the bike cranks over. If ever the bike quits or refuses to start that's the first thing I will look for.


Reading back over your earlier thread, this doesn't sound right, I'm sure the gear should be lined up in the centre of the hole, someone with a similar bike should be able to verify that for us, just pop the sensor out and take a picture down the hole.
Quote
Another possibly relevant fact.  When I remove the CPS from its hole in front of the crankcase, and I look down through that hole at the gear ring, the gear ring is not centered in the hole as I would have expected.  The tunnel can only "see" about half of the gear ring.  Half that space, towards the front wheel, has a gear present.  The other half, towards the rear wheel, if just empty space.  Of course, I don't know if this configuration is perfectly normal. I just would have assumed the CPS would be positioned in such a way as to see 100% of the edge of the gear.  Is it possible that somehow the gear ring has moved forward in such a way that the CPS can no longer reliably sense it and generate a signal?   (My clutch is beginning to slip too, which makes me even more curious about a possibly moving gear ring).

[malik]

FWIW, a similar sort of thing happened to the 2014 V7 Special (1TB, MIUG3 ECU), four times, between 58,649 km and 61,183km,  some 10,000km into the 30,000km trip around the country. Each time it occurred after refilling the fuel tank. Lights on, but no start. Leave for a minute or so, then OK. Hasn't happened since (now at 107,000km), so I suppose you could say it fixed itself. Another one of "life with Guzzis'" mysteries.

Somewhere along the line, I did smear a little Threebond 1211 on the rev sensor gasket ('tho can't find any evidence in my log).

About clutch slip - Around 100,000km the clutch started slipping (clutch push rod seal failed - oil up the push rod to the cup & over the friction plate and inside the bell housing - to check, remove the rubber bung at the inspection port on the RHS of the bell housing - if your finger comes out wet with oil mixed in with old friction pad dust, you've likely an oil leak in there somewhere & its most likely the push rod oil seal). I've had 2 of those seals go at around 100,000km - the V7C & the V7S - the V7C again has oil in the bellhousing at another 100,000km (precise cause yet to be confirmed, but the push rod oil seal is a likely suspect), a mate's Breva had oil on the clutch at 80,000km, and the 127,000km V7C the same. Another mate's 25,000km Racer has oil in the bell housing & a slipping clutch.

[Sasquatch Jim]

It just didn't want to carry you in good weather, and figured that in bad weather you wouldn't want to ride it.

[fubar guzzi]

       Aaaaaah that my friend is called a FUBAR moment,not many folks are lucky enough to experience such,you should feel fortunate! your bike will give the impression of self healing-----till it happens again!!! It's a hexxxx-----only way to remove hexxxx would be to buy Fubar beer at next rally           Coors Original please     

[dguzzi]

Only a few know how to do a timed curse. Perhaps you found one of the few?

[SmithSwede]

FWIW, a similar sort of thing happened to the 2014 V7 Special (1TB, MIUG3 ECU), four times, between 58,649 km and 61,183km,  some 10,000km into the 30,000km trip around the country. Each time it occurred after refilling the fuel tank. Lights on, but no start. Leave for a minute or so, then OK. Hasn't happened since (now at 107,000km), so I suppose you could say it fixed itself. Another one of "life with Guzzis'" mysteries.

Somewhere along the line, I did smear a little Threebond 1211 on the rev sensor gasket ('tho can't find any evidence in my log).

About clutch slip - Around 100,000km the clutch started slipping (clutch push rod seal failed - oil up the push rod to the cup & over the friction plate and inside the bell housing - to check, remove the rubber bung at the inspection port on the RHS of the bell housing - if your finger comes out wet with oil mixed in with old friction pad dust, you've likely an oil leak in there somewhere & its most likely the push rod oil seal). I've had 2 of those seals go at around 100,000km - the V7C & the V7S - the V7C again has oil in the bellhousing at another 100,000km (precise cause yet to be confirmed, but the push rod oil seal is a likely suspect), a mate's Breva had oil on the clutch at 80,000km, and the 127,000km V7C the same. Another mate's 25,000km Racer has oil in the bell housing & a slipping clutch.

Thanks Malik.  At 60,000 miles my original clutch went out.  I was leaking a lot of gear oil from the bell housing.  The gear oil leak was due to a failure of the bearing on the clutch side of the transmission input shaft.   When I took that bearing out it was severely worn and barely holding the balls inside.  I think that caused the shaft to wobble or vibrate, so the seal could not contain the oil.  I replaced the bearing, the transmission seal, the clutch, and the pushrod seals     Worked fine; no leaks.

But about 30,000 mile later the clutch is slipping again.  It works fine unless I try to go more than 75 or 80 mph, then slips.  No oil leaks.  I'm not impressed with the clutch life, especially since this is mostly highway miles and I am very gentle on the clutch and know its adjusted properly.

I didn't try to grind or resurface the face of the flywheel.   Was that a mistake?  I did thoroughly remove all possible grease and oil with solvents, and finished off with alcohol. 

On the plus side, I was able to find a barely used flywheel, clutch, clutch housing and associated parts for a measly $63.  Just need to talk myself into doing all the labor required to take out the old stuff and replace it.   

Or maybe just be lazy and let everything wear more.  I shouldn't be going more than 80 anyway, right?   

[Gliderjohn]

From SmithSwede:

I shouldn't be going more than 80 anyway, right?

From what I have heard if you are traveling below 80 in Texas you are asking to be a grease spot in the road.
GliderJohn

[SmithSwede]

From SmithSwede:From what I have heard if you are traveling below 80 in Texas you are asking to be a grease spot in the road.
GliderJohn

That’s kinda true John. Are you telling me to just buckle down and fix it right?

[malik]

Yes, if that bearing fails, it will wobble on the shaft and wreck the seal (ask me how I know). You won't know for sure which of the bell housing side seals have gone until you take it apart. As a matter of course, I now also replace the main engine seal. It's not cheap, but it's just sitting there looking at me and it's easy to do and seems to be common practice of those who know more of this than I do. To remove the oil from the flywheel and sprung clutch plates, I attack them with wet n dry until those leopard spots are a memory. The flywheel is too expensive to replace without first trying an alternative. Well done you for finding replacement parts at a good price.

I had better get a wriggle on and put together the blow by blow instructions for the 1TB bikes - there are significant differences in the dismantling procedure in these, as compared to that of the 2TB as set out in Nick Webb's Breva Gearbox instructions - well worth downloading (from here, or thisoldtractor or Moto-Guzzi-750-groups.io) & printing out. As with the 2TBs, the workshop manual is less than explicit in some of its pronouncements/instructions. You'll need space and cover and probably a few days to get the gearbox & clutch off (I have done it in a couple of hours, but that was only after doing it three times, back to back. The next time, a few years later, again took days). If you've done it before, you've probably got or have access to the special tools. I've also found that the flywheel holder for a VW Beetle works on the guzzi flywheel (I've seen them advertised for $7.95 in the US).


If you've another bike running, then there's less pressure. But, it then takes longer.

Good luck,

Mal

[SmithSwede]

Yes, if that bearing fails, it will wobble on the shaft and wreck the seal (ask me how I know). You won't know for sure which of the bell housing side seals have gone until you take it apart. As a matter of course, I now also replace the main engine seal. It's not cheap, but it's just sitting there looking at me and it's easy to do and seems to be common practice of those who know more of this than I do. To remove the oil from the flywheel and sprung clutch plates, I attack them with wet n dry until those leopard spots are a memory. The flywheel is too expensive to replace without first trying an alternative. Well done you for finding replacement parts at a good price.

I had better get a wriggle on and put together the blow by blow instructions for the 1TB bikes - there are significant differences in the dismantling procedure in these, as compared to that of the 2TB as set out in Nick Webb's Breva Gearbox instructions - well worth downloading (from here, or thisoldtractor or Moto-Guzzi-750-groups.io) & printing out. As with the 2TBs, the workshop manual is less than explicit in some of its pronouncements/instructions. You'll need space and cover and probably a few days to get the gearbox & clutch off (I have done it in a couple of hours, but that was only after doing it three times, back to back. The next time, a few years later, again took days). If you've done it before, you've probably got or have access to the special tools. I've also found that the flywheel holder for a VW Beetle works on the guzzi flywheel (I've seen them advertised for $7.95 in the US).


If you've another bike running, then there's less pressure. But, it then takes longer.

Good luck,

Mal

How exactly do you replace the rear engine main seal?  I’ve been thinking I should do that next time I get into the clutch.  Might as well.

Do you just extract the old one with wood screws or something?  Then drive the new one in square?

Do I need to heat the engine casing or freeze the seal?   Lube? Locktite sealant?

[malik]

The seals I've removed so far come out easily enough with a flat blade screwdriver.  If reluctant to move there's room in the seal for a self-tapper.

I use an appropriate sized socket to gently drive the new seal in square and flush with the outer body. I've mates who have the big block tool for this job, which also controls the depth, but, of course, the big block seal is 1mm larger than than the small block one. There's no heating or freezing necessary for any of the seals I've replaced in there or in the gearbox, they are made of a flexible material. A smear of oil on the seal seems to be enough. For some of the gearbox bearings, on the other hand, freezing the bearing works, and in one case, heating the case was needed as well. For bearings, good quality, jap spec ones are advised. The clutch shaft bearing on two bikes were a tad loose in the case, and I used a smear of a bearing glue on the last one. It remains to be seen if that's going to be effective.

[chuck peterson]

Why that’s the Popes blessing in action...

[SmithSwede]

One other data point.  Dusty and I had a theory that maybe the crankshaft thrust bearings had worn, permitting the crank to work forward, thus moving the ring gear beyond the ability of the CPS to sense it.  We got off onto that because the ring gear doesn’t look perfectly centered in the hole for the CPS unit as I would have expected.   

Yesterday I tried tapping the crank back towards rear wheel by whacking the nut on the alternator.   Then prying it forward with a screwdriver to the ring gear.  Pushing and pulling with Vice-grips attached to alternator nut.  I did this with the clutch out, and also clutch lever strapped back.   

I can detect no fore-aft play.  So I’m discarding that theory.   

Dunno what else to do but ride it and see what happens.  Will have a spare CPS unit and contact cleaner in my saddlebags.  Will get Guzzi-Diag cables.

[ScuRoo]

Hey SmithSwede
How Can A Guzzi Fix Itself?
Funny title pricked my interest - dunno if you ever got to the bottom of it but as far as I’m concerned...
Yes they can!

Here’s what happened to my V11 - it started to play up intermittently when I first went out to the garage to start her up. Usually would... but sometimes didn’t.

When it didn’t I’d do the starting procedure a few times, out of gear, stand down, stand up, jiggle jiggle, get off bike, get on again, maybe pop seat & look at fuses dumbly, put seat on, get back on, stand up, clutch in, curse pray... & Boom! 💥

There she goes again. Great!

So what was it in the end??

Well, I think it was Mario who told me many years ago & my memory is a little hazy but...

I used to park it after riding in garage with first gear engaged on its stand.
Apparently, with 1st gear engaged this causes the cutout button to be in a compressed state.

If the bike was running, in gear with clutch in & you put stand down it would cut engine out - a design feature.

Don’t know if your model is similar but probably has same Guzzi feature...
Anyhooo - don’t keep parking it in gear as this causes spring to weaken & button to stay stuck in the same position even when you popped in neutral to start.

I just stopped leaving it parked in gear & spring button doesn’t stick & it starts every time without any problem.

After reading your posts I suspect you may have had same parking habits but maybe when you parked it for the 5 months it was left in neutral - which allowed spring to push button out to proper position...

So when you eventually tried again... BOOM! 💥

All supposition on my part but for what it’s worth no harm in sharing with you... even if a bit belatedly! 🤔

[Chuck in Indiana]

I can detect no fore-aft play.  So I’m discarding that theory.   

There went my reply.
As I've said more than once, Caig DeOxit is magic in a can.. it probably fixed it.

[ozarquebus]

My G5 does that with the throw out bearing. It keeps knocking in neutral until some little gremlin in there opens the door and lets the Tommyknocker out for a while. Then it comes back after a few days to stay a little while.

[Bulldog9]

Good thread on Small Block issues, have it bookmarked for potential future issues on my Stornello.

As for the no crank no start, did you check the movement and function of the side stand switch? Just a thought, sorry if I missed it. I've had them gum up and move reluctantly on occasion, a loose connector and failing wire. May be worth a check.

[SmithSwede]

I only park the bike in gear when it is on an incline.    And yes, I thoroughly checked the side stand switch.

FYI, this problem occurred a bit more than a year ago, and I’ve had no issues since—I’ve added 21,000 miles. 

I know for certain there was some fault in the crank position sensor circuit.  The sensor looked fine, and passed the Ohm test.   I strongly suspect the 3 prong connector was at fault.  This is a low, 5 volt circuit so it wouldn’t take much resistance to screw things up.  I’m convinced the connector itself was grotty, and the De-Oxit needed some time to restore the connection.   Maybe not 5 months though. 

I now travel with a spare sensor just in case.  The Guzzi stuff cross references with Fiat and other cars, so with some internet hunting you can find them for about $25 (not the $300 dealer price). And at least once a year I work over this critical connector, and all the others, with De-Oxit.  Work fuses, relays, grounds, switches, etc.   

I learned two things since that episode. 

First, for about $75 you can buy a small wave form sensor which can detect this signal.  It would have been very helpful to me to know whether or not the sensor was outputting a signal or not.   Maybe Guzzi diag can do this too.   I couldn’t get a reading from a multimeter, and foolishly thought I needed a full blown oscilloscope to detect this waveform. 

Second, an old time Guzzi guru mentioned to me that these sensors were originally designed for a dry, oil free environment on some Fiat.   For decades Guzzi has been running them in a high oil spray environment.   Some of the sensors leak from the *middle* of the unit, since they were not designed to be oil tight.  So maybe the internal coils and wires get saturated with oil, which carbonizes and screws up the signal (even though it still passes the ohm test)

The fix is to put a drop of the Locktite wicking sealant onto that center post. 

[SmithSwede]

After looking back on my former posts I realize I might save somebody the mental aggravation I went through. 

Dusty and I developed a theory that the ring gear was shifting forward in such a way that the sensor would miss it.  We got onto that path because the ring gear does not look centered beneath the hole for the sensor.  It was a really beautiful theory.   

But it turned out to be false.  I never could induce any for and aft motion in the crank.  The ring gear never changed position after running.  And it’s been running fine in all conditions for quite a while.  So it was NOT a wandering ring gear. 

But, but, but that means it is normal for the ring gear not to be perfectly centered beneath the sensor hole!  In complete violation of what my OCD brain tells me must be the design spec. 

Go figure.  Thanks Luigi. 

So if you get bored over the holidays, pull your sensor and see if the ring gear is centered.  And if it’s not, tell yourself that that condition is okey dokey fine and normal.   

[RinkRat II]

     I've heard tell (from very reliable sources) that it could take up to six months for that Flux capacitor to fully charge. It seems yours only needed five! 

     Happy Holidays.
     Paul B

[jcctx]

!. Hire you a pretty girl from Haiti~
2. Buy a live chicken~
3. Put on some Reggae music!
4. Tell her to do her thing!!!